A note for all of the lasers that pop balloons: it's not the visible light that does that, but it's the IR laser light that has the point heating effect.
If you are modding a laser diode, please be extremely careful, and try to work with a camera that has IR capability (take the IR cut filter from a webcam and put a filter on it that shows IR only) as the IR beam may not be coincidental with the visible light beam, and is almost certain to have a different divergence to the visible beam (chromatic aberrations in the collimation lens).
You'll not know that you've fried your retina until you hear/feel the "pop" of your retinal tissue boiling..
You can have a properly bright visible light laser that has no IR component - that would be considered safe (if dazzling). However most of the cheap double-pumped laser pointers and all of the modded drive diodes will have huge leakage of IR. Using an IR sensitive camera was an eye-opener for me.