The after-party went pretty much as I expected. Small, mostly people I actually knew, and a lot of fun. If there were more people (like a lot more) I'm not sure how we would have managed.
My boyfriend and I were supposed to show up at 11:30, as the party officially started at 12, but I think we got there at like 11:55 xD Oops. However, it didn't look like much setup had been done or was even needed, other than the volleyball net, which they didn't set up until after we got there anyway. We didn't help with it either, though.
The first attendee showed up at the same time as my boyfriend and I, the same attendee who was the first to show up at Kin-Yoobi, about 10 minutes early, or more, if I remember correctly. I can't for the life of me remember ever showing up early to a con that I wasn't staffing or volunteering for, but to each his own.
A couple more people showed up shortly, at most I think there were 11 of us, with at least 6 of us being staff, heh. Not our best marketing technique, but hopefully it gets better. It wasn't advertised much anyway.
We played volleyball with my Pokeball beach ball, and it went over the fence twice >_< At least it went to somewhere where we could get it without climbing the fence (we had to go around). Then when we got too hot from playing, we got in the pool and played Marco Polo. Or as we called it, "Alphonse-Edward", "Haruhi-Tamaki", "Jenny-Brock", or something else that I seem to have forgotten. Personally, my favorite was Alphonse-Edward or Haruhi-Tamaki.
There was another party going on at the same place at the same time as ours, and they thought we were crazy, and didn't get in the pool until we got out. Heh.
Eventually, we got cold in the pool, and the food was ready, so we hopped out. There were burgers and hot dogs, leftovers from Kin-Yoobi, haha. We ended up just sitting and talking, and then slowly people started to leave. I think my boyfriend and I were some of the last to leave at around 6 or 7. The party was originally supposed to go until 8, but all the attendees were gone by 5. These things happen, I suppose...
As far as cosplay goes, one girl was dressed as "Chick Pit", a variation of Pit from Kid Icarus / Super Smash Bros. Brawl, I wore a yellow shirt, jeans, and my Pikachu ears, but later changed into Swimmer Girl from Pokemon Platinum when it was warmer. My boyfriend went as Biker Guy from Pokemon Platinum, but I forgot his hat at home =/ Chick Pit later criticized me via facebook for being "half-assed" because she "will always see Pikachu" when she looks at me, and admittedly, that Pikachu was rather half-assed. However, Swimmer Girl is really a complete and accurate cosplay, except my hair, but it was a pool party, so what do you expect?