Advanced Poker
Planning Poker is a basic part of the Agile process. We've optimised it.
We can play without cards. For short sessions, or when we need to re-estimate on the fly, fingers behind the back work perfectly. Big stories need both hands. Hands behind the back means "I'm ready to estimate", a crooked finger means "half a point", open palms means "I don't know". This works well in release planning when we're discussing descoping a card; the client agrees to a change, and we do a new estimate on the spot.
When we use cards, we use good ones - presented to us by a client, our Planning Poker decks have been custom-printed by moo.com and feature a bonus "WTF?" card as well as the usuals.
We play fast. The 'classic' approach is to talk about a story, explore all the options and implications, then finally estimate. When we do this, we nearly always get matching estimates. But it's time-consuming, and if we're not planning to implement the story straight away (in which case we needed to have the conversation anyway), it's wasteful.
So when there's a big stack of cards to get through - like after a User Stories Workshop on a new project - we play Speed Poker. We select a card, read it verbatim, and estimate. If the estimates all match up, we move to the next card - we were all thinking the same thing, and we've saved the time needed to have the conversation. If they don't match up, we use the classic approach for that card.
We play commitment poker. For new projects, or those without a stable velocity, we use commitment-based planning rather than velocity-based planning. That is, after each story is added to the plan, we check that each member of the team is still comfortable committing. This suffers from the same 'peer pressure' effect as normal estimation, though, and we solve it the same way: on three, thumbs-up means "I'm sure we can do this", thumbs-down means "I'm no longer sure".