http://store.dieselsweeties.com/products/bacon-is-a-vegetable-shirt-purple

This is the classic Charlie Brown ensemble.
http://oldglory.com/lp/product?product_id=001637CTTS&atc=froogle&utm_source=Froogle&utm_medium=PPC...

http://www.stylinonline.com/barrackobama.html

Very clever tshirt! Woot rocks.
http://shirt.woot.com/Forums/ViewPost.aspx?PostID=2705702

http://www.prankplace.com/tshirts_pedro.htm

Unicorns are fun, but puking unicorns are even better!

This t-shirt is fully customizable by adding your own name! Go to http://tinyurl.com/6vwpfj and check it out!
http://tinyurl.com/6vwpfj

love New York is a 30 year old design that is still fresh, stylish and going strong! This t-shirt design is recognized the world over as a symbol of the one and only big apple. Not only a symbol of New York City, this design also represents the great Empire State (New York State). So whether you hail from upstate of the the tri-state this t-shirt design will let the world know "I love New York!
http://www.generallyproducts.com

This is the coolest t shirt I have come across this year.
http://shirt.woot.com/friends.aspx?k=6281

Seinfeld
http://www.nbcuniversalstore.com/detail.php?p=58275&SESSID=af55f718f629f28b2e8e6cf58d99770a

We all know the origin from the Forest Gump movie :)
http://www.amazon.com/Happy-Face-T-Shirt/dp/B000FET0JS

http://www.thinkgeek.com/tshirts/gaming/7190/