My First Con(tm) was Tekkoshocon 03, since it's the local con and I thought I'd ease into it.
It was about this big ----> [ ] ...but still a fun little introduction to the whole thing. Sis and I went for one of the days, Saturday, I believe. Just wandered around and bought a couple of things and watched people play DDR and got bored out of our minds during the cosplay intermission and, y'know, stuff.
I had to leave halfway through the AMVs, though, from being all zoned-out and overstimulated. Yeah, I was a wimp.
It was fun, though. And hey, it set up the cooperation necessary for getting myself to Otakon, which was mega-fun.