I've just looked at the tags page and noticed that there aren't very many with tag wikis.
Other sites have been trying to make sure that at least the first two pages of tags have wiki entries.
I'll try and do some over the next few days, but it would be great if everyone could join in. Note you don't have to have 20K reputation - anyone can suggest edits. Moderators and those with 5K+ will see the suggested edits and will be able to approve and improve if necessary.
For every edit you'll get 2 points of reputation and as the excerpt and body count as two separate edits that's 4 points per entry. So get editing!
This is still a problem. I'll try and get some done over the next week or so, but any and all assistance would be appreciated.