There's quite a few places in New York with offer rental of projectors. However, one which has a very long history of good customer service is http://www.hwc.tv/projector_rentals_nyc.html
Depending on your area, there is a local Rentway or Aaron's that have these LCD projectors for rent. They may be a little pricey, so if you have a local rental store or Office rental store they may be able to rent the LCD projector for cheaper.
At the time of writing (June 2012) Rent Way do not list projectors among their electronics inventory. Unlike televisions, projectors tend to lose their value very quickly after they have been used and any rent to own store is likely to have extremely high rental rates because of this. Inventory changes so it's always worth taking a look at the web site to see if they have started to carry projection equipment. If they do, please take a minute to update this answer too.
I am sure you can rent out projectors (possibly from a school or even the libraries), but it would probably be cheaper to just go buy one. You can find one at Michael's for about $40.
There are companies that rent projectors online to people in the Boston area. One company that does so is http://www.DVDPhotographs.com
You can rent projectors from stationary stores. Or you can buy them from big box stationary stores such as Staples or Office Depot. They have employees who can help you there.
Dirty Projectors was created in 2002.
Infocus projectors are made for the office, home, classroom, and for all presentation needs. Infocus projectors can also be useful in churches and the courtroom. The projectors are for presentation purposes.
You can rent projectors from stationary stores. Or you can buy them from big box stationary stores such as Staples or Office Depot. They have employees who can help you there.
LCD projectors are by far the best
Most projectors have the means to be a rear and front projection system. The only projectors that are unable to do this are the cheaper projectors you find at Office Depot used for powerpoint shows.
NEC's multimedia projectors cost from $310 to about $5,000. They also make cinema projectors which are even more expensive.
I haven't seen a retro school projectors on the market today but, If you really like the old school projectors you can get some restored projectors for a good price. anonymous@oola.com