http://www.youtube.com/watch?v=L38wthA4Ld0

Dunno if I can even call this one meme, since it’s maybe previous to the concept.

Also known as Whassup? or What’s up? and other variations.
I remember publishing a post about this Budweiser ad on my first blog, years ago.
And I posted several different versions… maybe ten or more versions if I remember correctly.
I think this ad campaign became famous before YouTube even existed… or it was among the first very famous YouTube videos.
Here are some of them (not shure if I’ll ever be able to remember all of them though):

Pizza Guy:

http://www.youtube.com/watch?v=AiFEz6e5LCU

Wassabi:

http://www.youtube.com/watch?v=mZk7-1uGmc4

Wassup – Dookie’s Girlfriend:

http://www.youtube.com/watch?v=jcVfKWxtM0M

What are you doing:

http://www.youtube.com/watch?v=8PQogX88yjg

Alien Wassup:

http://www.youtube.com/watch?v=qGkRjduIngc

Grandmas:

http://www.youtube.com/watch?v=P3jJGDCczL4

’till here I think they are all “official”… the next ones are fanmade edits and tributes!

Wassup 2008 Obama campaign – VERY AWESOME! (notice they are the original wassup actors!):

http://www.youtube.com/watch?v=Qq8Uc5BFogE

Scary Movie Wassup:

http://www.youtube.com/watch?v=41RFw9aqIxM

Nintendo Wassup:

http://www.youtube.com/watch?v=iz69mkKcVDE

Simpsons edit:

http://www.youtube.com/watch?v=LZTyA1zsxyw

Superfriends Wassup:

http://www.youtube.com/watch?v=OkDPM5j_6hk

Transformers Wassup:

http://www.youtube.com/watch?v=4rUhKrffKRE

Grannies:

http://www.youtube.com/watch?v=mQk5weAjjwI

Kids:

http://www.youtube.com/watch?v=dVodKcavupI

Gah, enough!
Good times, good times.

Source: Gizmodo post and comments, plus some YouTube research.