In the ScrumProcess, the larger of two InspectAndAdapt cycles are called Sprints. Sprints are 30-days* (WhyThirtyDays?) in length, and must result in a potentially shippable increment of software. (Of course, when using Scrum on non-software projects this rule would become "must result in something of actual value".)
For the daily InspectAndAdapt cycle, see DailyScrum.
ScrumMethodology uses 30-day iterations called 'sprints'.
Another use of the word sprint has sprung up in the Python/Zope community, see PythonSprint.
Ham Radio Morse Code operators have 'sprints' where they make as many contacts as possible, at very high speeds. See the Fists CW Club http://www.fists.org for more details.