that is anice trap, i will do that in my future games

Many chess gambits in Russian http://2ls.ru/shahmatnye-debyuty

The Ben-oni is just one big positional trap.

Noah's Ark Trap, can come up in Ruy Lopez and Nimzo-Indian, two widely used openings.

Most effective traps? I'm not qualified to answer that. There are far too many. Since this thread has turned into posting cool traps for the sake of being cool traps though... Blackmar Diemer players will know about the Halosar Trap, which appears in the Ryder Gambit. I don't ever play the Ryder Gambit, as I think it's pretty bad for White if they avoid the trap and defend correctly.

The Teichmann Exchange leads to its own sort of 'Halosar' trap though, which is equally devastating.

Interestingly, the line in Shepi's game has occurred twice in my database. Bent Larsen was white in one, and drew. In another, a Master ended up winning in 17 moves... as White!

It's a brilliant, really deep trap. But scoring only 25% isn't very effective, especially considering the work required to remember it.

It took work to find it, but not really to remember it. I was shown the position after move 8 for black to move as a puzzle, and knew it came from a slav. Took me a long time in database searching to find the actual line, but not that hard to remember when you had to try to visualize the entire line for a few hours straight (not even knowing if it was a tactic or positional move).

I know, black can always play 3: .. Nf6, getting the c3 sicilian, which is known as either equal or slightly better for white.

lol what pretty much all openings its either equal or slightly better otherwise players who play white will not go into that opening and also the smith morra gambit is dangerous but unsound if the black player knows what he is doing and c5 is the most popular reply to e4 more popular than e5 so it is defeinatley 'sound'

That's how white should play, but I believe there is some move like maybe 15...Bb4+ that is an improvement. White must try something like f4 later, winning g7, after which the material is even but black's queenside majority is more important than white's kingside one.

It is an overly complicated line to go into just to try to get the advantage of a queenside majority, I will admit.