I've seen them repurposed as candle holders and as glasses. I've seen them reused as part of a bottle tree. I've seen them melted into spoon rests. I've seem them made into part of a fence (which was very, very cool looking.)
We reuse most of ours for wine, but dh only likes a certain kind for that. I've got some with neat labels that I use to water plants with. Otherwise, into the recycling they go.