  A generic search for anomalous production of events with at least three
charged leptons is presented. The search uses a pp-collision data sample at a
center-of-mass energy of 7 TeV corresponding to 4.6 inverse femtobarns of
integrated luminosity collected in 2011 by the ATLAS detector at the CERN Large
Hadron Collider. Events are required to contain at least two electrons or
muons, while the third lepton may either be an additional electron or muon, or
a hadronically decaying tau lepton. Events are categorized by the presence or
absence of a reconstructed tau-lepton or Z-boson candidate decaying to leptons.
No significant excess above backgrounds expected from Standard Model processes
is observed. Results are presented as upper limits on event yields from
non-Standard-Model processes producing at least three prompt, isolated leptons,
given as functions of lower bounds on several kinematic variables. Fiducial
efficiencies for model testing are also provided. The use of the results is
illustrated by setting upper limits on the production of doubly-charged Higgs
bosons decaying to same-sign lepton pairs.
