Republican presidential candidates transformed the campus of Iowa State University into a conservative carnival Saturday, competing for votes by offering free soda and barbecue and a promise of shade for the thousands who braved the 100-degree heat to attend this year's straw poll. The activists came by the busload, more than 30,000 in all, for the first voting of the 2008 presidential campaign. But for many, casting ballots was an afterthought as they made their way past huge stages with live bands, inflatable bouncy rooms for the kids and fair-style booths touting one conservative cause after another. The Iowa Right...