Registered Republicans and Democrats all over Colorado will be attending local precincts to take part in the caucuses Tuesday.
But some may be wondering, what does this all mean? And just what happens at a caucus?
Well the phones at the two party offices in Colorado Springs have been ringing off the hook with people asking just that question.
Bottom line, Tuesday night is probably your only opportunity to have a voice in who your party nominates to be a Presidential Candidate.
"This is where people really have the most power and the most voice in local politics." says Nathan Fisk of the El Paso County Republican party.
John Morris of the El Paso County Democrats agrees.
"This is the time where you have a voice on who gets placed on the ballot, if you don't participate in the caucuses you sit on the sidelines until November."
The caucuses are basically just a neighborhood party meeting.
You go and express your opinions on issues and which presidential candidate you support.
Then, you vote for delegates or representatives who will take your opinions to the next level.
The reason, Presidential candidates care about Colorado's caucus so much now is because for the first time, a poll will be taken giving them a really good idea of who people would vote for.
"Tuesday night all of the Republican presidential candidates will get a very clear snap shot of where Colorado is at in regards to those candidates." says Nathan Fisk.
And who might receive the presidential nomination at the Democratic and Republican national conventions this fall and this year, it sounds like voters really want to get involved.
"Both candidates on our side have generated a tremendous amount of enthusiasm not just because of their gender and their race but because of their ideas, " says John Morris.
In the past, Colorado has held their caucuses later and they never polled voters, so when the primary rolled around months later most candidates had dropped out and it was pretty much already decided. This year is different.
So now, more than ever before your participation matters.
If you aren't a registered Democrat or Republican, you are out of luck.
But if you can participate and want to find out where to go click on campaign 2008 on the top of the page.
Caucuses start at 7 Tuesday and should last about an hour and a half.