What's a mini stroke like?

Like a big one but..: Ministroke is generally a term applied to small clinical deficits resulting from a stroke--it does not apply to causation nor to specific symptoms. The same factors responsible for major strokes are often responsible for "mini" strokes. Symptoms depend on function of brain tissue affected. Duration depends on many factors.

Mini stroke is: Also called tia. See stroke.Org for good discussion. Pay close attention to risk factors and try to improve those.