As for the design, a lot of clothing stores these days are selling so-called "graphic Ts". These are highly designed T shirts with anything from abstract words to, basically, advertisements for cool-sounding places that the wearers have never been to. They sell because they look great, and make the wearer look cool. I'd like to take inspiration from these designs, and the looks they have, which are self-evidently appealing to today's public to do designs that reference the Venture Cafe. They don't need to use the logo in any way.
For content: The designers can look to the http://www.venturecafe.net website and the VenCaf blog for inspiration in terms of what words or images to include. They could include the logo, or just the words Venture Cafe, or the words "Cambridge, Massachusetts", or "MIT" and maybe "Harvard", or words from the Venture Cafe credo, words from interviews or videos about the Venture Cafe that they find on the site or on the blogetc. This is an artistic exercise, and we're asking them to be creative.
For design style: I don't see any reason they shouldn't take inspiration from the best-selling graphic Ts retailers that are doing creative things with the category. Here are two retailers that I think resonate well with the concept: