What are some simple reality checks I can perform?

[uberyoshi]

I'm trying to make it a habit to do reality checks whenever I can. The quickest and most discrete thing I thought of was to just stop and look at my hands. The thing is, it doesn't feel like enough. I saw a post a while back about someone who looked down and noticed his hands had turn into claws, but what are the odds I'll have the same experience? Are there any small reality checks you do that are easy to make a habit out of? I've heard of the old look at a digital watch and then look again - has anyone gone lucid from that? Edit: I feel noobish. I just found the reality check tutorial. Well, I guess the question is still relevant - what do you use as a reality check, and when?