In other news my group finished Siege of Bordrin's Watch last night with a magnificent 20 round encounter. I had read about the final encounter on WOTC's community pages. Some groups claiming it went 40 rounds and hundreds of minions were killed. I'm not exactly sure why a DM would let it run that long, but 20 rounds was definitely a lot of fun.
I run with only 4 players so I had to adjust the encounter on the fly, using different waves to tailor the difficulty to keep my PCs challenged, but just barely keeping them from being overwhelmed. I think I managed to hit the difficulty just about right. With the exception of the ranger who killed minions by the dozen, everyone was at the very least bloodied and most of them had been one lucky hit away from making death saves at some point in the encounter. I probably should have thrown a bit more ranged damage at the ranger just to challenge him a little.
Since I knew it would be a long encounter and since numbers heavy encounters (i.e. ones featuring lots of weak npcs) are rough on an undersized group, I used the idea from the DMG 2 on Long Fights. I planned for one of two events to be a "turning point" in the battle. When the PCs completed the mini-skill challenge or when the PCs defeated the enemy leader they would be offered the choice of one of the following:
1) Regain 1 healing surge
2) Regain use of Second Wind
3) Gain an Action Point and be able to spend it, even if they had spent an AP this encounter
4) Regain use of an expended Encounter power
The party managed to kill the leader before doing the skill challenge, so that became the turning point. No one picked option 2, but every other choice was taken. Giving them that little extra boost of power really did turn the battle in their favor (although just barely). I'm not sure if the DMG 2 included the idea to let the player's pick or if that was something I thought up, but I feel it was key to making this idea work. There was really no single benefit from the list above that would have fit everyone.
It's not hard to see why many people rate Bordrin's Watch among the best adventures in the heroic tier. It borrows a lot from the LotR movies, is well paced, and unlike Rescue at Rivenroar has a final encounter that actually has that epic end of the movie feel to it. Definitely thumbs up for Siege of Bordrin's Watch and the DMG 2.
For those of you who are really interested, I'll do a write up with quotes, pictures, etc over on the groups Obsidian Portal adventure log .