Good portable mini projector are reasonable priced and versatile, and you can easily use them in many kind sof locations. Good mini projectors can show 50-inch plus images easily.
Just pick one wall, and wherever you can find a white surface, start the show.
Overall, a portable mini projector is good for the occasional show.
The best portable mini projector: AAXA P300 (bright, multiple inputs, can be put closer to the wall)
The second best portable mini projector: LG PH300 (bright, more accurate colors, integrated TV tuner, longer battery life, bad contrast ratio)
The best ultraportable mini projector: Asus S1 (carrying case, good in low-light situations)