“Misty Mountain Top” is a really nice and very underrated song by one and only Led Zeppelin, from their fourth album, to be specific. For me it stands out a bit with the fact it actually has a riff and it's a really cool one! Even KISS couldn't help stealing it for their song “Uh! All Night”, hehe. Anyway, back to the song... It starts with a simple and groovy riff, but don't relax too much, because those improvisations John Paul Jones plays in choruses can take a bit of your time. For me personally it wasn't so hard to play them as it was hard to keep them all in my head :) I mean there are 5 choruses and 5 different bass parts for them... Still, it was a lot of fun to learn and play it.
P.S. There are several versions of tabs for this bass part online and it seems like I just created another one. However, I think it's sort of close to the original + has a few slides, because I love slides :)