I once heard someone say that If you're going to Common Grounds for the coffee, you're missing the point.
If you want to meet some bizarre strangers, this is a lovely place to do so. The fastest way to make new friends here is to have a pack of cigarettes and give them out.
I go to Common Grounds for the people watching, the free internet, the random outbursts, and the startup card games. I've taken pregnancy tests in their bathroom and comforted depressed people on the benches just outside. I've stargazed with a gorgeous emo girl in their parking lot at 3 AM and pulled what feels like a thousand all-nighters here.
This is NOT a quiet coffee shop. Expect loud music and barking emo kids.
I rarely come here before midnight. I always stop in when I'm driving back from Chicago and it's 3 AM and I just need some human contact.
It's 24 hours, so when I'm a lonely insomniac, this is where I go. It's probably the only place I feel comfortable going when I've had a bad night out, cried off all my makeup, but am not ready to go home yet.
There's more about this place, plus pictures, on my blog: (http://whatsincleveland.blogspot.com/2011/03/common-grounds-24-hour-place-for.html) ... I'm the one in the hat, in the last picture. If you see me there, by all means, say hello.