Check out this contact printing with blueprint (diazo) paper and Windex window cleaner tutorial by Mark Gutierrez. Cool results, no darkroom or enlarger required, dead easy!
Read instructions at Instructables
Thanks to Seth for the heads-up!
Photo by Mark Gutierrez, Creative Commons Attribution-NonCommercial-ShareAlike 2.5 license
f295 DIY Photography Forum member unrealalex has posted an excellent tutorial with step-by-step photos on building a contact printing frame for about US $20 in materials.
Contact printing frames are used for holding negatives and photo paper together (no enlarger involved) in many alternative printing processes.
Read instructions at f295