Colorado Senate Bill 13-0011 creating civil unions for same sex couples in Colorado (basically, a domestic partnership with all of the state law legal incidents of marriage other than the name "marriage" which is prohibited by the state constitution of the State of Colorado) was approved by the state senate today.
It now moves to the Democratic Party controlled House of Representatives where it will be assigned to a committee on a first reading, referred back to the full house for a committee of the whole reading where amendments may be offered after passing in committee, and then will face a final vote on passage on the floor of the state house. If any amendments to the bill pass in committee or in the committee of the whole, then either the state senate must readopt the version amended by the state house without amendment, or the matter must be referred to a conference committee to work out a version acceptable to both houses. The most likely outcome is that the state house will pass the bill without further amendment.
Once the bill clears both houses, it will be effective when signed by the Governor who has stated that he will sign the bill. An almost identical bill had enough votes to pass last session on the final days of the 2012 regular legislative session but failed to become law because the Republican leadership chose to end the session. The bill was then killed in a gerrymandered committee to which it was referred in a 2012 special session of the Colorado General Assembly was convened by the Governor to address the matters left hanging as a result of the premature ending of the regular session, after the regular session ended.
The bottom line is that sometime in 2013, Colorado will join the ranks of states that have either gay marriage or civil unions.