With four weeks until Election Day, the race for the Congress continues to be the same, with Republicans favored to hold on to the House, while Democrats seem to poised to keep the Senate, though there could still be all kinds of different outcomes.

The poll numbers in a number of Senate races remain very tight, with Real Clear Politics listing 11 different seats in the "Toss Up" category at this point in time.

Seven of those seats are held by Democrats - Connecticut, Missouri, Montana, North Dakota, Ohio, Virginia and Wisconsin.

Four GOP seats are toss-ups: Arizona, Indiana, Massachusetts and Nevada.

Let's do a quick thumbnail on the toss-ups for Senate:

Arizona (R) - Republicans thought this was a slam dunk, but Rep. Jeff Flake (R) has not been able to put away former U.S. Surgeon General Richard Carmona.

Connecticut (D) - Democrats thought this seat was a lock, but Rep. Chris Murphy (D) has struggled in the race against former WWE executive Linda McMahon.

Indiana (R) - Republicans have a tough race on their hands here for the seat of Sen. Richard Lugar (R), who was defeated in the GOP primary by State Treasurer Richard Mourdock; he hasn't been able to shake Rep. Joe Donnelly (D-IN).

Massachusetts (R) - Another GOP seat that might be in trouble, as Sen. Scott Brown has trailed in recent polls against Democrat Elizabeth Warren; she has led in 7 of the last 10 statewide polls.

Missouri (D) - This was another seat that was supposed to be a GOP lock, but the primary victory of Rep. Todd Akin (R) has given Missouri Sen. Clare McCaskill a new lease on life; she has led in eight of the last nine polls.

Montana (D) - This race in Montana is expected to be close, as Sen. Jon Tester (D) and Rep. Denny Rehberg (R) have been battling for months; the polls have slightly favored Rehberg.

Nevada (R) - Along with the Obama-Romney battle in the Silver State, Democrats still think they have a chance to win a seat from Sen. Dean Heller (R), who has led most of the polls in recent months, but one out a few weeks ago had a tie with Rep. Shelley Berkley.

North Dakota (D) - This is another example of seat that the GOP already had down as a victory, but it isn't turning out to be easy. Rep. Rick Berg (R) is being given a run for his money by Democrat Heidi Heitkamp; no one will be surprised if the Democrats spin an upset here.  New polls out today show Romney leading in North Dakota by 14 points, but the Senate race is a tie.

Ohio (D) - In both Florida and Ohio, the polls have been all over the place in the race for Senate; here, Sen. Sherrod Brown (D) is still favored to win over State Treasurer Josh Mandel. The last four polls on this race have had Brown up by 8 and 9 points, ahead by just two, and one that was a tie. But like in Florida, Democrats think their Senate incumbent can run stronger than President Obama.

Virginia (D) - Another seat that Republicans thought they had a very good chance to win, now seems to be trending a bit to the Democrats. Former Sen. George Allen (R) has trailed former Gov. Tim Kaine (D) since Labor Day; 9 of 10 polls have been in favor of Kaine, the other was a tie. This race could also be impacted by the Presidential battle in the Old Dominion.

Wisconsin (D) - When ex-Gov. Tommy Thompson won the GOP primary in August, Republicans thought this would be their seat, but that may not happen now as Rep. Tammy Baldwin (D) has surged since the Democratic convention and has led in the last seven polls in the Badger State. Again, turnout for the Presidential election could swing this race, too.

Republicans are the big favorites to win at least one Democratic seat in Nebraska, as former Sen. Bob Kerrey (D) is not given much chance to keep that seat in the Blue column.

One other seat to mention is Florida, where Sen. Bill Nelson (D) has led in most polls, though there was a great example on Monday of how wacky the polls can be - one new poll had Nelson ahead by 11 points, another had him tied with Rep. Connie Mack (R).  Nelson remains the favorite.

The GOP needs a net gain of at least four seats to take charge of the Senate, three if they can win the race for the White House and have a Vice President to break a tie vote.