Here's an idea I had for getting into other people's dreams:
Casting Time: 1 minute
Range: 10 feet per two caster levels
Target: One creature per two caster levels
Duration: Eight hours or see text
Saving Throw: Will negates
Spell Resistance: Yes
This spell can be cast either awake or from in a lucid dream. If it is cast while awake, it has it's "from inside a lucid dream" effect, but delayed until the caster and at least one target fall asleep. When cast from inside a lucid dream, the caster and all targets (targets are chosen from people sleeping within range in reality, not from dream-figments) join a communal dream (and are lucid while in that dream). This is basically the same as any other lucid dream except that there are multiple actual people present in it.