The filters package is notable for being a peice of software I didn't realize I was writing until years after I released it. At first I thought I was just collecting some old text filters that had been floating around usenet for ages. Only later did I realize that most of that stuff wasn't free enough to go into Debian, and that if I wanted these silly filters in the distribution I'd need to rewrite many of them. Now the package is evenly split between filters I've rewritten and filters that I've gotten relicensed with an acceptable license.
The other interesting blind spot I've had about filters is that until last month I didn't realize there was no reason for it to only be a Debian package. Now that I've begun to look, I've found out that the code from it has spread its way around to a variety of other places without me paying attention.
I don't write games.. well, aside from MOOs, so filters and shoop (which I'll write about when I get up to 2000) are the only software I've released that was just done for fun with no real purpose.