Myself is a reflexive pronoun.
It is used to reflect back to the subject of a sentence. For example, in the sentence “I gave myself the day off“, “myself” reflects back to the subject “I”. On the other hand, in a sentence like “Joe, Bill, Jim and myself went to the game last night“, “myself” has nothing to which it can reflect. In sentences like this it is better to use either “I” or “me” (in this specific case, it would be “I”).
There seems to be a tendency for people to use “myself” incorrectly (particularly among bloggers). I do not know why. Maybe they think it sound less presumptuous than using “I” or “me” or that it sounds more intellectual. Unfortunately, it only sounds lazy and awkward.