Everyone should be using an auction format for their drafts, of course, because science.
But for the semi-enlightened, who still use snake drafting but have at least persuaded their leaguemates of the wisdom of FAAB, my favorite fun rule is to run either a blind bid or an auction just prior to the draft for draft slots, with the highest bid getting 1st choice of draft position, next-highest getting 2nd choice, and so on. The amount of each owner's bid is removed from their FAAB for the year (e.g. we use a $200 FAAB, so if I bid $30 on draft slot, I get only $170 for the season).
Even if you don't use FAAB, you can run this blind bidding / auction exercise for draft slots using real money, and just add it to the overall pot.
Lots of fun, adds another layer of strategy, and adds only 5-10 minutes to the overall draft process.