ColoradoPols has a list of election dates
that I will republish here for local readers.

2006 Election: Key Dates

• Jan. 23: Last day to affiliate
  with a political party in order to vote in the precinct caucus.
• March 21: Precinct Caucus Day.
• March 27: First day to begin circulating candidate petitions for Primary Election.
• April 1-20: County Assemblies (click for Democrat or Republican)
• Mid-May: Congressional District Assemblies.
• May 20: State Assembly (both parties).
• May 25: Last day to file candidate petitions for Primary Election.
• July 10: Last day to register to vote for the primary election.
• July 28: Last day to apply for an absentee ballot for the primary election if the ballot is to be mailed.
• July 29: Early voting begins for the primary election.
• Aug. 4: Last day for early voting; last day to apply for an absentee ballot for the primary election if the ballot is not to be mailed.
• Aug. 8: Primary Election Day.
• Oct. 10: Last day to register to vote for the General Election.
• Oct. 23: Early voting begins
• Oct. 27: Last day to apply for an absentee ballot for the General Election if mailed.
• Nov. 3: Last day to apply for an absentee ballot for the General Election if not mailed.
• Nov. 3: Last day for early voting.
• Nov. 7: Election Day.