Seq24
Seq24 is a software MIDI music sequencer that runs under Linux and Microsoft Windows. It is designed to be simple to use and appropriate for live performance.
Distributed under the terms of the GNU General Public License, Seq is free software.
Seq24 is intended to be similar to hardware sequencers/samplers such as Akai's MPC line of instruments. It works by sequencing smaller sequences or loops of MIDI notes and performance information into larger music sequences in a manner similar to the way in which Sony's Acid software is used to sequence audio clips.
While developed from 2002-2006 by Rob Buse, a team picked up the project in 2008 with Rob's blessing, and resumed work with release 0.8.8.