Warhammer 40k is a wargame involving miniatures that is set in the 41st milenium. This is a time of great strife between the various inhabitants of the galaxy. These include humanity, eldar (space elves), orcs, tyranids (insect like monsters), squats (space dwarves) and many others.  

I collect eldar and I have got an army of about 6000 points. My brothers, James and Tim, collect orks and space marines.

This site contains a number of eldar pages including tactics and new units so follow the above link to find out more.