If you have not already checked it out, Pinterest is a really cool website. My friend, Nichole, got me hooked and I really love it. I believe it requires an invite, but if you go to the website you can request an invite and you should receive one promptly (I believe it took a day).
The thing about Pinterest is that in addition to seeing lots of cool ideas and things, you can search for things as well. If you are throwing a Halloween party, you can type "Halloween party ideas" and you'll get TONS of stuff. Change the wording to simply "Halloween" and you'll get a whole different set of ideas.
Anyway, it's a really cool site and I recommend it. So far, the only drawback seems to be that you cannot start a "private board." This can be a problem if you are looking to pin ideas for a specific birthday/celebration that is a surprise and the guest of honor is following you on Pinterest. Perhaps one day they'll allow for private boards. Until then, happy pinning!