What do you do to boost morale with your Joes?

Nothing boosts moral like time off. Period

I say thank you with great Christmas Parties (informal), send them on chopper flights, give them dinner certificates, BBQ for them. Of course the first step is to treat them with dignity and respect.

You have received good advice from the other respondents. The truly best thing and I am summing up what everyone else has said is give your Joes some down time but keep it informally organized with a meal (BBQ is always good) letting the troops show their cooking skills. Let them let down their hair but don't let it turn into a gripe session! Keep it spontaneous.