Ha, that's great.

I knocked up a more or less working FreeCell solitaire in Excel one bored afternoon, so Blackjack should certainly be possible in plain old Excel VBA.

Most impressive Excel things I've seen by other people: a Game of Life (I'm guessing not SeanDav's, but who knows!), a Dijkstra's algorithm demo which let you resize cells and recalculated the shortest distance between two cells, and this rather impressive Enigma cipher encoder/decoder: http://news.ycombinator.com/item?id=3755656

Essentially, excel is a functional language, without the ability for recursion. If there were a built in array datatype, that'd be possible. There's a few papers floating around explaining an integration between Haskell and excel, described in some places as hsExcel, but I haven't seen a working copy.

That's nuts