An open source project I contribute to uses wine in a pretty cool way I think. Actually it's mentioned in these wine release notes - LMMS.
It's a music production studio, and one of the features that it offers is to use a VST instrument. A VST instrument is a .dll file which provides a virtual instrument for the user to use in their music project. So here we have this native linux app but it is able to take advantage of .dll plugins using wine.