Nice. I never have done this in a game, but there are enough puzzles ending in one to make up for it.
Finally...

What a coincidence! My first smothered mate was on this very same day!
Nice job sacrificing the rook 6 moves before the actual mate. I doubt I would have thought of that.

That was a cool game! I saw two mistakes done by your opponent - getting his queen stuck in a corner and letting your knight to c6 taking off the protection by his knight. You did very well to exploit it fully :)

I looked over this game and have to say it was played with amazing precision. Of course the 1600 rated player made a few blunders in the opening. Namely forgetting development and keeping his king in the center along with some just poor decisions. However, not a move or tempo was wasted, and the rook sacrifice was very deep and deserves an (!).
And ending with the Queen sac and smothered mate...Well it deserves an "immortal game" stamp of approval.
A few moments later....
Being really impressed with the play in this game I entered the game into Fritz to have it analysed for white:
Inaccuracies: zero
Blunders: zero
(!): 2
(!?): 0
(??): 0
Fritz agreed with every move 100%...of course giving some recommendations on what it thought was slightly better in a given position. However every single move was at least found at a depth of 12 as being a sound move. And to have two exclamations in one game is in itself worthy of an "immortal game" for a sub-1500.
So yeah I would put this one in your list of best games played.

Wow thanks everyone for your applause, and thanks especially to immortalgamer for the analysis.
The reason my rating is so low is because I usually tend to play too fast.
Karl, (hope your tracking this) in answer to your question, find your game, Click download PGN to notepad copy it, go to the forum you want to post it in, click on the "insert position or game" click game or sequense of moves, and then paste into the PGN file and insert.
My first smothered mate on this site! Please comment on the game.