It is not often that I will recommend that teachers spend money. Budgets are tight and we need to make every penny count. Therefore I only recommend books, technology, resources that I have used and have felt it worth the cost.
It is with that in mind that I encourage you to check out Mr. L's Math. He has a lot of great resources on his blog but what I have found most useful are the books and DVDs found at Teacher to Teacher Press run by Bill Lombard (Mr. L) and Brad Fulton. I have always been passionate about having math games in the classroom that also promote learning and Mr. L has quite a few books related to that subject.
In fact every single game I have played with my students from these resources has been a big hit with the students. Additionally, they are retaining the information and understanding it more deeply. If I am referring to a concept I can say, "Remember when we played..." and they will quickly remember and understand what I am talking about. Supplementing my math curriculum with games that have no cost except the cost of paper (see my post about how to save paper) and take up as little or as much time as you would like has brought a fresh air of enthusiasm to my students and I.
If this were all, then I would appreciate the books but they would not warrant an entire post on BrokenAirplane. For the last year I have been passionate about creating projects where the student learns by doing the project. For those of you uninitiated to the world of Project Based Learning, many times the learning is "front loaded" or taught in a traditional method as a means to completing or understanding the product. To me this undermines why I would do projects in the first place. If I want the students to learn by doing, then I needed projects which have them learn through the project itself.
As an integrated math/physics teacher I find it easier to create physics projects because they are more based in concrete reality (electricity, forces, motion, etc). Yet, the more challenging concepts to students are often the abstract concepts in math (negative numbers, geometric constructions, fractions/ratios). This is the other reason I was so grateful to find Mr. L's resources as their store carries a DVD simply called Math Projects. You will find these projects to be cost effective (often using just paper and free software) and able to be completed in a day or two. This, as they say, allows the benefit of using projects while still maintaining your districts' curriculum pacing.
Finally, I have seen many teachers in twitter #edchat and various blogs comment on the desire to have students writing in their math class. Spending time explaining or analyzing their thinking would greatly benefit the students ability to solve different or more difficult problems. Having read "The Language of Math" I can tell you that the team of Mr. Fulton and Mr. L do a great job of describing why and how this could be implemented in a classroom with effective tips and prompts that you could begin using tomorrow.
I realize that the cost might make you hesitate, but there are samples of student work of which you can get inspired from, and samples from the books themselves so you can see whether or not they will fit your classroom.
I am excited that my students are doing hands on learning with math and spending time playing with it in a way that is inviting to all. I hope that you will consider using these resources in your classroom so you too can enjoy the benefits.