Try the Petrov defense
Help me Choose an Unsound Opening Repertoire

Try the Petrov defense
Sorry, but the Petroff (1.e4 e5 2.Nf3 Nf6) is perfectly sound and doesn't count.

For Black you can try 1 e4 b5?!
I've actually won a few games with this, it's so obscure it doesn't even have a name.
But, it's probably better than the Fred :) The idea is that after 2 Bxb5 Bb7 White has to defend the e pawn, and Black has some scope for nasties.
The funnest line:
[edit: Bxh1, the game annotation should say]

OMG I just snorted coffee through my nose!!!
What a great line. I will definitely give 1.e4 b5 a try, thanks for the tip.

Currently, my favorite unsound opening as White is the Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7) with 75 wins, 2 losses, and 2 draws.
1.e4 b5 is probably unsound, but if you are playing for fun, why not. I have played it 6 times against weaker players.
Can you prove that it is sound?
Soundness is like scientific theory. Can only be proven by the weight of evidence, compiled over time. Likewise, soundness can be completely undone by one instance (line) of unsoundness.
The Petroff is in as good a shape, theoretically, as any opening can possibly be.

Why you have do play unsound openings ? Better play openings that are considered unsound, but in reality are not.
Take the Englund as example, the majority of people claims it to be unsound, but in my opinion its not and perfectly playable.
A few suggestions :
1.Nf3 d5 2.e4 Tennison gambit
1.d4 Nf6 2.g4 Gibbins Weidenhagen gambit
the whole 1.Nc3 and 1. .. Nc6 gamma
1.e4 c5 2.b4! Sicilian Wing gambit
1.d4 c5 2.d5 Nf6 3.c4 Ne4 The Vulture
1.d4 c5 2.d5 Nf6 3.Nc3 Qa5 The Woozel
1.d4 c5 2.d5 Nf6 3.Nf3 c4 The Hawk
1.e4 Nf6 2.e5 Ne4 Mokele Mbembe
I have tried a number of these suggestions, but I will give the Lembert-Tennyson gambit a second try. I haven't tried the Mokele Mbembe and the Gibbins Wiedenhagen but will do so. I do own Bucker's excellent book on the Vulture (and Hawk and Woozle). Thanks for the suggestions.
I am intrigued by the other suggestion -- 1.e4 e5 2.Bc4 Nf6 3.d4 -- is it really unsound and how could it lead to a surprising outcome?
Keep the ideas flowing!

Why you have do play unsound openings ? Better play openings that are considered unsound, but in reality are not.
Take the Englund as example, the majority of people claims it to be unsound, but in my opinion its not and perfectly playable.
A few suggestions :
1.Nf3 d5 2.e4 Tennison gambit
1.d4 Nf6 2.g4 Gibbins Weidenhagen gambit
the whole 1.Nc3 and 1. .. Nc6 gamma
1.e4 c5 2.b4! Sicilian Wing gambit
1.d4 c5 2.d5 Nf6 3.c4 Ne4 The Vulture
1.d4 c5 2.d5 Nf6 3.Nc3 Qa5 The Woozel
1.d4 c5 2.d5 Nf6 3.Nf3 c4 The Hawk
1.e4 Nf6 2.e5 Ne4 Mokele Mbembe
I have tried a number of these suggestions, but I will give the Lembert-Tennyson gambit a second try. I haven't tried the Mokele Mbembe and the Gibbins Wiedenhagen but will do so. I do own Bucker's excellent book on the Vulture (and Hawk and Woozle). Thanks for the suggestions.
I am intrigued by the other suggestion -- 1.e4 e5 2.Bc4 Nf6 3.d4 -- is it really unsound and how could it lead to a surprising outcome?
Keep the ideas flowing!
No it's not unsound: check this site
http://www.rci.rutgers.edu/~goeller/urusov/gambit/index.html
I've been tricked twice by the Tennison gambit. It was very poor play by me last time, but the opened and unstable position surely helped the outcome.
Can't remember every move, but it was something like that:

Blackmar-Diemer of course.
This line in the Reti -- advance variation is dubious yet playable:
1.Nf3 d5 2.c4 d4 3.e3 Nc6 4.b4?!

Aha. I had seen the Urusov Gambit in the books before, but I forgot about it. That one might be a little too mainstream for me .
I used to play the Boden Kieseritzky gambit (1.e4 e5 2.Bc4 Nf6 3.Nf3 Nxe4 4.Nc3) but in that line Black can return the pawn and get a safe position, or play 3...Nc6 with a standard Two Knights.
One issue: for all 1.Nf3 d5 gambit lines (both Tennyson and 2.c4 d4 3.e3 c5 4.b4), I would also have to figure out how to continue against 1...Nf6.
The Damiano might be a brilliant idea. I wonder how to play it if White doesn't try 3.Nxe5 however.
I am writing to ask the members of chess.com (my future opponents) to suggest some unsound openings that I can try out. I play chess entirely for fun, and I don't mind losing sometimes. That said, I usually win with my current set of unsound openings.
Feel free to post links to games or analysis for me to consider. I promise to try out the best ideas.
Right now as Black I've been playing the Fred: 1.e4 f5? 2.exf7 Kf7?? which I've been really enjoying. After 3.Qh5+ g6 4.fxg6+ Kg7 5.gxh7 Rxh7 6.Qg5+ Kh8, Black is clearly losing. But he often develops surprising counterplay and White can easily drift into trouble, and I've won a lot of games with this opening. (Sometimes I feel bad because it must be embarrassing for White.) I used to play the Elephant Gambit 1.e4 e5 2.Nf3 d5?! 3.exd5 Bd6!? and I may go back to that line some day.
Against Queen pawn openings I've been playing the Englund Gambit 1.d4 e5. Against the English I've been playing 1.c4 g5 2.d4 Bg7.
My opening strategies for White are less unsound and I'm definitely looking for some good ideas to try against 1...e5 as well as the Sicilian, French, Caro-Kann and Pirc/Modern defenses.
My goal is not to simply play bad moves, but to play unsound moves where I am objectively worse, but I nonetheless have a chance to get good counterplay. Even if it's not unsound, I still might play something if it's highly unorthodox and aggressive.
Thanks in advance for your input.