I recently acquired a nice second-hand 17bii (the real deal, not the + model). My wife and I have been house shopping, so I've got an excuse to grab a financial model to complement my stack of scientifics.

So with that out of the way, let's (ab)use the solver a bit. Here's about 10 minutes of tinkering and familiarizing myself with the cooler features: the Fibonacci sequence.

FIB:IF(S(NEXT):NEXT:INIT+L(A:0)+L(B:0)+-L(NEXT:1))=L(B:G(A))+L(A:G(NEXT))

Solve for INIT to get the first term of the sequence, and solve for NEXT to fetch subsequent terms.

Anybody else have some interesting - and not necessarily useful - solver routines? I'm sure a chess-playing program is out of the question, but has anybody tried tic-tac-toe?

Oh, and it does a damn nice job of financial calculation too. :)