  It is shown that a IIA superstring carrying D0-brane charge can be
`blown-up', in a {\it Minkowski vacuum} background, to a (1/4)-supersymmetric
tubular D2-brane, supported against collapse by the angular momentum generated
by crossed electric and magnetic Born-Infeld fields. This `supertube' can be
viewed as a worldvolume realization of the sigma-model Q-lump.
