From: US Legal
Some insightful information on Juror Summons.
A juror summons is a process issued by the court commanding the appearance of an individual to attend and be available for duty on a petit or grand jury at a specified place, time, and date.
Appearance for jury duty is mandatory unless the potential juror is excused from appearing. The U.S. Constitution and all state constitutions guarantee its citizens the right to a jury trial in both civil and criminal cases. A person who fails to respond to a jury summons may be subject to a contempt of court citation. The person may also have to serve a short jail sentence or pay fines.
Jurors are selected on a random basis from state departments of motor vehicles and voter registration lists. Any person who is 18 years or older, a U.S. citizen, and is not a convicted felon whose civil rights have not been restored may be selected for jury duty.
A jury summons will indicate which court is demanding the citizen’s presence and the date on which the person is required to appear. Generally, a jury summons is sent by mail. However, the serving process, and the contents to be included in the summons may vary from state to state
The following is an example of a state statute (Colorado) relating to juror summons:
C.R.S. 13-71-111. Contents of juror summons.