Weird results in textured viewport shading

I was working on a model in Blender Render and switching back and forth between textured and solid viewport shading. Suddenly one of my meshes started looking really weird, as shown in the pictures.

The first picture is taken from above and the second from below. This happpens in both singletexture and multitexture shading, but works fine when I render the image. The GLSL shading makes the model look normal in the viewport, but when I press P to start the game I made the model for It looks exactly as on the pictures. I’ve tried recalculating normals and re-installing blender(I’m using version 2.68) but it doesn’t help. I have no idea what I am doing wrong since the other objects are shaded properly.