The Department of Energy has formed the L Prize, or the Bright Tomorrow Lighting Prize, which it describes as
the first government-sponsored technology competition designed to spur lighting manufacturers to develop high-quality, high-efficiency solid-state lighting products to replace the common light bulb.
This is one of their solid-state lighting design competitions.
It seems like some of the details are still being worked out, but you can get a rough idea of the prize from their announcement:
The competition will award cash prizes, and may also lead to opportunities for federal purchasing agreements, utility programs, and other incentives for winning products. ... The legislation challenges industry to develop replacement technologies for today’s most widely used and inefficient products, 60W incandescent lamps and PAR 38 halogen lamps. Today’s L Prize program announcement specifies technical requirements for these two competition categories. A future L Prize program announcement will call for development of a new “21st Century Lamp,” as authorized in the legislation. ... The legislation authorizes up to $20 million in cash prizes; the exact amount of the cash prize for each category will be determined based on DOE Congressional appropriations and supplemental contributions from foundations and utilities. DOE will contribute up to $1 million to the cash prize purse, subject to enactment of the FY 2009 appropriation. In addition, potential opportunities for future federal purchasing agreements, utility programs, and other incentives for winning products may far exceed the value of the cash prize.