Hi Gringo,
Picture activities are good at any level - as they get more advanced you simply choose more complex pictures.
Interactive storytelling can also be used, or try this
fluency activity, which can be used from intermediate levels up, but works best at advanced level.
Discussions based on
music and visualisation often go down well.
Another thing you might try is
debates,and then how about an adult version of "show and tell" - in reality a small presentation? Each student gives a short (max 5 mins) presentation on a topic of their own choice, and while they talk each other student must think of at least two questions, additions or objections for the follow up stage. Topics are endless but might include : my work/studies, an object which has great sentimental value for me, what I love/hate about my home town, etc.
Hope that gives you some ideas!
Sue