Ray's is the perfect way to stay in shape for the winter! Situated on Cleveland's west side and offering 140,000 square feet of indoor mountain bike/BMX riding, Ray's offers something for everyone from raw beginner to pro level. Bring your own MTB or BMX or rent one there. Here's a link to pricing: http://www.raysmtb.com/about/prices.html. Note the link at the bottom for 1st Time Visitors special pricing.
As huge as Ray's is, it can be a bit difficult to locate. Punch "Ray's Indoor Mountain Bike Park, Walford Avenue, Cleveland, OH" into Google Maps and an icon will appear exactly where the front door is located. Notice there's no ROAD that actually goes there; this is because once you turn off Walford Ave, you drive through the parking areas of this complex until you get around back. Look for all the cars with bicycle racks.
There are small lockers if you'd like to lock up your valuables while riding. Bring your own lock. There are plenty of areas to relax as a spectator, so feel free to invite friends/family that would just like to watch. Admission is free for non-riders.
Vending machines are on-site, but for anything else you're welcome to bring your own; families often do entire picnics there while their kids ride, and Domino's is a frequent visitor there as well.