http://www.irregularwebcomic.net- I'm pretty sure this isn't as big of an intenret phenomonom as some other webcomics out there- but I wanna see how many people out there are fans of IWC. I think its very funny, but then again, most of my favorite jokes are when he pokes fun with physics, which some people may not get.
If you like tabletop RP'ing, you'll like this. All the different storylines are supposedly different tabletop RP's he plays in his spare time and he chronicles the events of them in webcomic form. Mostly uses Legos and miniature character figures.