PJ's?

[Minnitonka]

I use my husbands light weight pajama pants and a T shirt- works well for me and its comfortable.

[TammyLynn]

I had a pair of fleece bottoms and a nylon t-shirt I slept in. There's just something nice about changing out of grubby hiking clothes and putting on a pair of comfortable camp clothes! After you've been out in the woods for a while, it's the simple things that make you smile...

[sbhikes]

Don't try to recreate your home life on the trail. That's a recipe for a too-heavy pack. Leave the PJs home. All you need to do is wash yourself off with a bandana and then you can sleep in your long underwear, if you have them, or in your hiking clothes if they aren't too wet. Heck, you can sleep in your rain gear, too.

[Creek Dancer]

I suppose you could sleep in your rain gear, but you would have a hard time warming up your sleeping bag. The rain gear would prevent your body heat from warming up the bag.

But sbhikes is right. Trying to recreate your homelife on the trail would probably mean carrying way too much stuff. I sleep in synthetic or wool long underwear which doubles as an extra layer to keep me warm around camp, if necessary.