Startups offer many opportunities, both in tech and across a diversity of functions/industries from marketing to healthcare to online services. Startups need people who can work on strategy, branding, finance, and every other functional area, and the organization’s lean staffing means you will probably get a chance to get your hands on many different parts of its operation.
Another benefit to consider: startups can have a short hiring cycle (not all do!), which makes it possible to create a role for the summer even if you’re just reaching out now. Startup experience will provide great stories, powerful operational experience, and exposure to interesting people. It can also be attractive to employers looking for leaders in consulting, strategy, or general management. Startups offer a chance to take initiative, deal with ambiguity, and work in close-knit teams.
In addition to networking your way to a startup, you might consider checking out these sites; though their job listings are likely to be for full-time, permanent positions, it will give you an idea of what companies are out there that may be of interest to you, as well as what their current needs might be.