First session results
In the end, to keep things somewhat consistent with the book, I went with something like what's in the moment of prescience spell. You can spend a hero point to get a bonus equal to char. level on one d20 roll, or AC against one attack, or the DC for one save. You have to declare the use before the dice are rolled (change from the original, where you could declare after the roll).
The players each got d3+1 hero points, refreshing at each level. The exact number of points was hidden, but I told a player if he was down to his last 2.
All of the players saved their points for the climactic encounter, preferring to slog their way through the minor stuff early on. I may have contributed to this by foreshadowing that there was going to be a "dragon" at the end. (Really a half-fiend 10-headed cryohydra with bat wings and 20' flying speed -- basically a poor man's dragon.)
During the final fight:
One of the players boosted a Bluff check sky-high, to convince the hydra that he was switching sides. Then he gave out a ton of false info, causing the hydra to waste a round doing sub-optimal stuff -- eg breathing on the guy with protection from cold, bashing up the knight with AC 31, etc.
The barbarian made an 8' running high jump to smack the hydra for more than half its hit points. It would have been more if he'd spend a point on a crit confirmation roll. The plan was then to bounce off the hydra and land safely back on the ground, unfortunately the next Jump check was completely flubbed and the barb went for an unplanned swim.
The knight blew all 4 points (!) to boost his Ref saves, after getting breathed on by all of the hydra's heads. He was the only one with a flight item, so he kept charging after it while most of the group was down on the ground. Even after this, he got dropped to 1 hit point away from falling unconscious. And he still kept going after it!
Hero points got given out for:
- Aforementioned Bluff roll, which was the most crazily original use of a Bluff I've seen in a long time.
- The barb doing the bounce-off-the-hydra thing, even if it didn't come off. Acrobatics always goes down a treat with the audience.
- The knight who kept attacking even when nearly dead. This sort of damn-the-torpedoes-full-speed-ahead attitude is exactly what I was hoping to encourage.
All in all, things worked out pretty good. People seemed more willing to take risks and attempt wild stunts, and it really helped spice up the game.
They were spending the points at a rate of knots though, which is something I might have to look at. OTOH I guess eventually they'll run out of points, so the problem might correct itself.