I put my macbook to sleep this morning, and went to class as usual. However, 2 hours later I noticed my bookbag was extremely warm. I took my macbook out and it was so hot I could barely hold on to it. I opened the lid and nothing happened... so I restarted. When it booted up it was at 70+ degrees Celsius. The screen was hot, the keypad was hot, everything felt like it was on the verge of melting. I boosted the fans to max with SMC and let it cool down.. There doesn't seem to be much damage, not that I can notice anyway, but how can I prevent this from happening in the future? And has it happened to anyone else?