Pick random cell in VBA

[Flammy]

Hi there I'm trying to pick a random cell in a range (A1:BW30) and change the background color of those cells. This would then be repeated say 50 times. There can be repetition in the cells picked but if its easy to prevent repetition that would be awesome. Ideally this would all be in a sub procedure. I tried modifying some code from here: http://www.access-programmers.co.uk/forums/showthread.php?t=161420 but I kept getting an invalid range error

Thanks in advance!