C-SPAN (Cable-Satellite Public Affairs Network) is a cable television network.
Unlike nearly all cable channels outside of those operated by local governments which broadcast such events as school board and city council meetings, C-SPAN is not a channel which pays to be included by cable and satellite networks; instead, the networks subsidize the cost of its operation by providing it without cost to the company as a public service (thus the name). (In the early days of cable and satellite television it was a popular channel to be the first removed due to its non-paying status, only to have subscribers inundate the networks with requests to keep it in the lineup.)
Its main showings are live coverage of proceedings of the United States House of Representatives (broadcast on CSPAN, its original channel) and the United States Senate (broadcast on CSPAN2). When not in session it airs coverage of political events such as Presidential speeches and Congressional committee hearings, as well as the highly popular "Prime Ministers Questions" from the United Kingdom Parliament when it is in session.
In addition to the two channels mentioned above CSPAN operates a third network —CSPAN3—as well as a radio network and web resources.
On those times when it allows call-ins on a subject CSPAN operates three separate phone lines: one for Democrats, one for Republicans, and one for Independents.