It's late; I spent a lot of time preparing my nationwide modeling software, but here's a quick look at the Arkansas Senate race, per Rasmussen. It's a mess.
Rasmussen doesn't seem to do primary polling, so he just polls every likely combination of candidates in the general election. In the case of Arkansas that means 10 different matchups, as Bill Halter is challenging incumbent Senator Blanche Lincoln for the Democrats, while the Republicans have five challengers in Kim Hendren, Gilbert Baker, Curtis Coleman, Jim Holt, and John Boozman.
The biggest news: Lincoln is in trouble should she make the general. Four of the five Republicans are pulling in 51%, Lincoln never goes over 36%, and the five in all have an average lead probability of 94%.
Bill Halter runs much better. Republicans all lead him, but they range from Curtis Coleman (who also runs weakest against Lincoln) at 40-37 (63% chance of Republican lead), to John Boozman leading 48-34 (94% chance of Republican lead). Republicans against Halter have an average lead probability of 80%, meaning Halter is running 14% better than Lincoln.
Halter/Coleman would apparently be a close race at this point. Boozman/Lincoln would make this a safe Republican seat. Both primaries will be important to watch, though the five-way Republican race might be impossible to handicap well.