How long is yours?

I've been pondering ride lengths recently and what makes a ride an epic and what makes a ride a long ride. Here's the definitions I think I using right now
  • a spin - less than 10 miles - 1.5 hrs
  • a ride - more than 10 miles - 2 hrs
  • a medium ride - up to 20 miles - 2.5 hrs
  • a long ride - up to 30 miles - 3 hrs
  • an epic - over 30 miles - 4 hrs plus
What do you think of that definition? Some rides slip up and down a step depending on terrain so you can count on either the distances or time. As long as you're riding hard seems like the names hold up to me.