I like...It could be worse, it could be raining.(from Young Frankenstein as they are grave robbing)(I use that one alot)
Also..What hump?

Also like several from Monty Python...Oh, uh, well if we build a badger...

How about...Fat and stupid is no way to go through life son.(Animal House)

Blues Bros has too many to even try to list. I do like the one posted above as well.
Might have to rent that one for Christmas instead of the forty yr old virgin this year.