there are lots of trails around Grays Lake connecting it with most of downtown. The trip around the lake is just shy of 2 miles, which makes for a nice walk during your lunch hour. Be careful of bikes and rollerbladers on your trip around. You can rent paddleboats and canoes there and I think aqua bikes. There is a beach area, and also a concession stand there, too. And there are several safety phones if needed.