Rent Glass is a mail oder Lens Rental Company. They are currently renting a nice selection of Canon lenses, but plan to start offering Nikon Lenses shortly.

They have some really nice expensive lenses that you can try out to see if you like them before you buy them, or if you just need them for a limited time. The rates are reasonable, and so far I'm very pleased with them.

I currently have Sigma 15mm f/2.8 EX Diagonal Fisheye with me. I wish I would have had it for the trip to Hawaii last week.

Anyway -  the rates are reasonable, and the send you everything you need to return the lens back to them.