Wikipedia for Mac

Features:

• Compatible with any language wikipedia, just enter the 2 (sometimes 3 or more) letter code on the back. Defaults to English.
• Back and forward buttons with page caching. The cache life time is user-configurable on the back of the widget.
• External links open in your preferred browser.
• Click the 'wikipedia' button to the left of the search field to open the current article or search term in Safari.
• The little '?' button to the left of the search field will pull a random article into the widget (Special:Randompage query).
• Back and forward buttons with page caching.

See http://www.whatsinthehouse.com/widgets/ for a list of known bugs and to-do's.