I already know of my two crossovers, whicha are part of the same series on FanFiction.Net and Twisting the Hellmouth (http://www.tthfanfic.org/Series-1194): First Meeting and A Call Away. I've also posted First Meeting in my LiveJournal, but the sequel won't be going up until I finish it.

And here are some of the fan fics I've already found...

+ A Good Day by Bugeyedmonster (http://www.tthfanfic.org/story.php?no=11017)
+ But Its Pretty Pink And Flowery by Bugeyedmonster (http://www.tthfanfic.org/story.php?no=17261)
+ Cadets Special Agent Edgerton Never Had by FlitShadowFlame (http://www.tthfanfic.org/story.php?no=13859)
+ Faith Never… by Bugeyedmonster (http://www.tthfanfic.org/story.php?no=17262)
+ In Another Life by Lyl (http://www.tthfanfic.org/story.php?no=17816)
+ Into The Woods by Elisabeth (http://www.tthfanfic.org/story.php?no=17863)
+ Jitters by Angelskuuipo (http://www.tthfanfic.org/story.php?no=12175)
+ Kidnapped by Nox (http://www.tthfanfic.org/story.php?no=13270)
+ Magic In Numbers by Elisabeth (http://www.tthfanfic.org/story.php?no=11186)
+ Smart Person by Cold Hands (http://www.tthfanfic.org/story.php?no=16003)
+ What Are The Odds? by Elisabeth (http://www.tthfanfic.org/story.php?no=12103)

And several others in the Numb3rs section of Twisting the Hellmouth (http://www.tthfanfic.org/main.php?list=1862&full=0&page=1), but those are the ones I really remember. Most of ‘em are short but funny, a few have more depth/chapters/etc.

So, again, can anyone recommend some more?