Wikipedia has various contests from time to time -- for good writing, site and logo designs, or great images or media -- to encourage and recognize brilliant, unusual, or specially-targeted contributions.
Contests have also been run on various other Wikimedia projects, generally eliciting excitement and support; the Wikinews writing contest in March/April and the second German writing contest (part of the International writing contest) both attracted over 10 unusual prizes from the community to hand out to the lucky/skillful winners.
You can also add to Ideas for new contests if you have a good idea for a contest.
|Wikipedia:International writing contest||-||Closed||ca March 2005||A coordinated contest across a number of Wikipedias.||winners | on meta|
|Deshipidian 2008||-||Closed||ca 2008||arranged by WikiProject:Bangladesh|
|WikiCup||2016||Closed||1 Jan 2016 - 31 Oct 2016||Results|
|WikiCup||2017||Future||1 Jan 2017 - 31 Oct 2017 ca 2007||Signup|
|Bacon WikiCup||2010||Closed||Adding bacon-related content||Winners|
|Bacon WikiCup||2011||Closed||Adding bacon-related content||Winners|
|Bacon WikiCup||2012||Closed||Adding bacon-related content||Winners|
|Wiki Loves Women Writing Contest||2016||Closed||15 Jan 2016 - 31 Jan 2016||15 days to create (at least) 15 biographies on notable African women|
|Military history Contest|
|Wikimania 2005:Writing contest||2005||Closed|
|Danny's contest||2004||Closed||Oct 2004|
|Danny's contest||2004||Closed||Nov 2004|
|The Core Contest||2016||Closed||15 May 2016 - 30 June 2016|
Current and future contests
- Wikimania competition
- An extended media contest, combining a contest for media gathered while at or en route to Wikimania, with a general contest for all content produced this year.
- Wikipedia:WikiSnap Challenge
- Wikipedia:The Great Wikipedia Dramaout, for 5 days, starting July 18, 2009, Wikipedians are being asked to voluntarily refrain from editing all non-article areas of Wikipedia, and instead dedicate themselves to creating, cleaning up, and building articles.
- Wikipedia:The Great Backlog Drive
Past and completed contests
- meta:Mascot - "Contest" for a Wikipedia mascot
The Wikimedia Foundation (WMF) advises  that although there is no problem in general with third parties running contests on Wikipedia, contest organizers should note the following:
- The contest should not be presented as if it was being organized, sponsored or endorsed by the WMF. This includes using the Wikipedia/WMF logos, which are trademarked and may only be used with the permission of the WMF (see Wikipedia:Copyrights), or implying that the WMF has any involvement beyond hosting the platform being used. (If you are unsure about your contest in this regard, please contact liaisonwikimedia.org.)
- Contributors are liable for their own contributions, which include the people running such contests.
- Organizers may wish to obtain advice on contest law before attempting to run a contest, on-wiki or elsewhere.