What do I need to know about riding in rain?

I think it would be fun, as long as it was only rain, not too heavy, and no lightning or severe weather within hearing distance!

Do bikes have a lot more probs on wet roads than cars?

I rode after it rained this week and one corner had a lot of mud that had then been tracked up the street by car tires. I took that very carefully -- I could imagine how slick it was!

But beyond the obvious, is there anything to be aware of about riding in the rain?