I coated a piece of cardboard with strips of Shurtape DC 181 to make a shade-reflector for my CFL's. Appears to work so far.

Also have a huge roll of Reflectix... that is reflective bubble-wrap type insulation used for radiant barriers. Anyone use this stuff? Looks like mylar. I'll report back...

Shurtape at Lowe's: 2" x 120 yd. Flex Duct Tape

Reflectix at Lowe's: 4' x 25' Double Reflective Foil Insulation