The Rules

NFL: 100 points to first place, 80 points to second, 70 points to third, and so on, with last place getting zero.
MLB: 90 to first place, 70, 60, 50, 40, 30, 20, 10, 5, 0.  You get the idea.  As the game shrinks in value, so do the point totals for finishing further down.
March Madness Bracket: 80 to first place, etc.
NBA: 70 to first place, etc.
College Football Pickem: 60 to first place, etc.
NHL: 50 to first place, etc.
NASCAR: 40 to first place, etc.
Golf: 30 to first place, etc.  (Is this sufficiently devalued? Too devalued?)
BONUS POINTS: +20 to whoever is the champion of the most sports.

One added wrinkle will be the possibility of cross-sport trades. Still working out the details on this: we may end up allowing for trades across any sport, but the trade has to include at least one player on either side for evaluation’s sake - not just another draft pick. In other words, you could conceivably trade Paul Pierce for Marc Bulger and a sixth round pick in the MLB draft, but NOT just a player for picks swap.

This may be the only restriction, however - other than trade deadlines in each sport to prevent last week pre-playoffs trades in head to head leagues.