One's a leprechaun and the other's a leper-con.
You can mash potatoes, but you can't pee soup. (sorry sorry. Really. I've loved this joke since I was... oh.. six...)
One trains the mind the other minds the train.
Aw shucks!
The Easter Blarney!
A Leper-Con
Didn't the Trojan horse burst open & thousands of little guys poured out Less than stellar marketing.