Intersection testing:
Collision detection:
Line (or ray):
R(t) = O + Dt 
Sphere:
P  C = r 

Triangle
P_{0}, P_{1}, P_{2} 

Axisaligned bounding box (AABB):
X_{min} <= x <= X_{max} Y_{min} <= y <= Y_{max} Z_{min} <= z <= Z_{max} 
Oriented bounding box (OBB):
B_{center} B_{u}, B_{v}, B_{w} 
Plane:
Ax + By + Cz + d = 0 or N * P + d = 0 
Techniques:
Dot product facts:
V dot V = V^{2}
Dot product of V with a unit vector u is the length of the projection of V onto u