He did an interesting cover[1] of Elton John's Rocket Man[2] back in 78.

That cover was later remixed into this[3] piece of internet gold (IMHO).

[1]: https://www.youtube.com/watch?v=8wI4jMxveyI

[2]: https://www.youtube.com/watch?v=r_QZe8Z66x8

[3]: https://www.youtube.com/watch?v=-IffZh3V8oQ

And Shatner's cover was covered by Family Guy:

https://www.youtube.com/watch?v=XZL4pNtI9nM