Here are some things I like to meditate on.
- plastic coffee-cup lids. Put your finger on the lid and feel the vibrations. When this works it's very obvious, so if it's not-working you might have the wrong type of lid (or be in a place that is not sufficiently vibrating – I haven't figured out the requirements yet, if you do please let me know).
- bubbles in drinks. Works well with beer, the bubbles are bigger and the contrast darker than water or soft drinks. (I don't actually like beer, I prefer to meditate on other people's beers)
- wind on skin. It is weirdly intriguing to me how hard it is to figure out what direction a breeze is coming from just by trying to feel it. Just trying to experience wind becomes an excellent object of meditation.
An underlying insight, which may be obvious to some but was not obvious to me, is that you can meditate on very fast/flickering things as well as on very slow things. There is a kind of meditation where you are trying to experience sensations flickering into an out of existence – to see that the movie is not one continuous object but a series of frames, each arising and disappearing in an instant. And this has changed my experience of experience.