Presidential hopeful Barack Obama and former President Bill Clinton will be in Colorado this week, ahead of the state's caucus next week.Obama will speak at Magness Arena at the Ritchie Center at the University of Denver Wednesday morning.Ray Rivera, State Director for Obama's Colorado campaign, said excitement is building leading up to Super Tuesday."Senator Obama is inspiring thousands of people who have never participated in the process," Rivera said.Doors are open at 8:30 a.m. The event is free and open to the public, however, space is limited and an RSVP is recommended. To RSVP click here or call Obama for America in Colorado at 303-825-3481 or 303-927-8135.Bill Clinton will also be at the Ritchie Center Wednesday evening, to rally supporters on behalf of his wife, Sen. Hillary Rodham Clinton. Doors open at 9 p.m."We have this broad network of support across the state and we just need to make sure they know where their caucus is and they get there on time," said Tyler Chafee, State Director for the Clinton Campaign.Clinton will also be hosting a $100-a-plate fundraising reception at the J.W. Marriott Hotel in Denver at 6:30 p.m.President George W. Bush also will visit the Denver area Thursday to raise funds to support the U.S. senatorial campaign of Bob Schaffer. The $ 5,000-a-couple fundraising event will be held at a private Cherry Hills Village home.Schaffer is running against Rep. Mark Udall for Wayne Allard's U.S. Senate seat.Their visits come as a recent Denver Post poll shows Obama and Hillary Rodham Clinton running neck and neck among Colorado voters.The poll shows the Illinois senator with 34 percent to 32 percent for Clinton, but the poll has a margin of error of 3.5 percent.University of Denver Political Science Professor Seth Masket said Obama and Clinton see Colorado as an important player since larger states like California and New York don't appear to be heavily contested."They're already very likely to go for Senator Clinton, so Colorado is one that's still in play and there's a fairly good chunk of delegates that could be useful," Masket said.On the Republican side, Mitt Romney has a 19-point lead over second-place Sen. John McCain.State Republican Party Chair Dick Waddams tells 7NEWS an announcement from at least one of the candidates about their Colorado campaign plans is expected in the coming days.Colorado's caucuses will be held Feb. 5, the same day that 23 other states will hold their primaries or caucuses. The day is called Super Tuesday because 52 percent of the Democratic Party delegates and 41 percent of the total Republican Party delegates are at stake.