It is too late for google, microsoft and facebook - their hiring processes for summer start in winter (I even know some guys who had interviews in november) and most places are taken; you can however try autumn if you want - I know that fb hires for autumn now.

Try some smaller ones - you are on site dedicated to startups so you should find some that hire! My algorithm when searching for interns was going through lots of companies, look into their jobs/careers for interns ad and sending my cv, starting from the most intersting.

Edit: I didn't have lots of projects to show either, but many companies don't really ask for them during interview (however for some it's a must - eg my friend wanted to work in android apps startup and they wanted him to already have something done for android) - algorithm puzzles seem to be popular, also you may be asked to read/write some code and some easy questions checking what you wrote about technology you mentioned in cv. That's really all I think.