What Wikipedia really needs, it occurred to me recently, is an article about the complexity class PPP. Not everyone will agree with that assessment; some people reckon that what Wikipedia really needs is to get rid of its liberal bias. For myself, I gave up waiting for the article on PPP to appear, made a account at Wikipedia, negotiated the rather unconventional syntax you use to edit articles, and wrote the above-linked-to page (that is, the first one, not the second one). Then I added links from the articles on PPAD and PPP (disambiguation). Then I wrote an article about the complexity class PPA, which as the whole world needs to know, is another denizen of the terra incognita that lies between PPAD and FNP. And if you think there's anything wrong with any of those articles, don't come hassling me about it, go and edit the pages yourself! It's not like they belong to me.
Then I contributed fifty quid to Wikipedia, after repeatedly seeing all those fundraising appeals from its founder Jimmy Wales.
Then I added most of the content on the current version of the page on the Research Excellence Framework (REF). Like the fundraising appeals, the REF is a bit hard to ignore, at least for UK academics. If you don't know what it is, consider yourself fortunate. If you want to know, follow the above link, it's as good a starting-point as any, in my unbiased opinion.
Happy new year, by the way.