jgbrowning said:
If I had an unlimited budget I'd buy Dungeons and Dragons from WoTC.
This is my answer as well.
And I don't think most of the answers here are responding in the correct range: "Enhance The D&D Experience" I think meant "for everyone" not just "for you". Who cares about spending millions on a room you and your six friends can play together in?
With an unlimited budget you could:
1) lose money advertising the game on commercials.
2) create gaming books that are worth hundreds of dollars and PAY HOBBY SHOPS TO GIVE THEM AWAY FREE and still pay the authors/artists/developers.
3) hire experienced DMs to provide free introductory adventures for people who ask about the commercial.
4) produce a REAL D&D movie or two or one hundred.
5) create a cable network for RPGs with televised (and well-edited) gaming sessions. (Now that's a money sink!) (Probably need to piggyback off GSN in reality, but with unlimited funds, you can "convince" the cable providers to put your network right on channel 3 or 4 in all markets.

)
6) product tie-ins with McDonalds/Coca-cola/You-name-it. (A D&D mini in every happy meal, win D&D books in soda bottle caps)
7) create FM/satellite broadcast stations in all markets playing "mood" music 24/7. The mysterious channel, the battle channel, the travelling music channel.
8) have congress/parliment/whatever-governing-body-you-have declare August national D&D month. (Think of the odd PSAs.)
9) ensure all releases are translated into the major languages of the world and that these translated volumes are released the same day as the original releases.
and that's just to begin with. Think BIG.