For now? Scummbuddy points us to a recent Archive.org, where 2,500 DOS games can be played to free through an emulator (DOSBox as it seems). Which games, you may ask? A quick search reveals:
The Secret of Monkey Island
Monkey Island 2: LeChuck's Revenge
And so on, read the full LucasArts list for more. I haven't taken much time to look at this, but LeChuck's Revenge requires the code wheel at least.
I assume all of this must be legal and all Actually, I don't assume that at all, so go look for both LucasArts and LucasFilm games while you still can.
Update: Turns out this is all a whole lot more legal than I had expected. Archive.org is, as it seems, exempt from the Digital Millennium Copyright Act, due to their efforts to preserve our digital history. A simple summation of that can be read right here.