This is a funny powerpoint that walks students through identifying triangles by their sides (equilateral, isosceles, scalene) and by their angles (acute, obtuse, right).
As this type of geometry can be extremely dull, I've packed in many jokes, fun facts and one critical thinking challenge. My students loved it.
Also included is a sample introductory demonstration. I teach a large number of ESL students and they sometimes have difficulty understanding that shapes can have more than one name. (Ie. an equilateral triangle can ALSO be an acute triangle). The demonstration is extremely simple, but very, very effective.
***You can find this activity for free in my store. It is called "Introduction to Classifying Triangles Powerpoint" and is an MS Word Document ***