How can I subdivide a triangle so there is a vertex in the center of each triange? For example, I have an icosahedron and I want to put a vertex in the middle of each face so I can make a dodecahedron later. However when i try to subdivide it it does the reasonable thing, to divide each into 4 equilateral triangles. Is there a way to do what I explained above?

Thanks.
Try the Poke tool (&#9095; AltP):