I am a Mason, as is my father, and both of my (deceased) Grandfathers. Often, many relatives of Freemasonry learn of the Craft, and thence go on to participate.
In most states, it is not permitted to invite a man, even a relative, to participate in Masonry. The organization stresses free will, and free association. IMHO- We go a little overboard in this respect.
I was introduced to masonry by a (now deceased) friend. One of my hobbies is Amateur Radio. I like to build radio sets, and communicate by morse code, etc. One of my radio friends was at a coffee meeting one time, and another man walked in, who did not know my friend. The two of them started shaking hands, and talking like they were well-acquainted.
I was fascinated, and I asked Don, "What is this all about?". He went on to explain that both he and the other man were Masons, and that all over the world, men who were masons would greet each other in like manner. I was hooked, right away, and I went to the local lodge, to get a petition (application form). I have been a mason for 25 years now, and I have attended lodges in 11 states, Washington DC, and three foreign countries. I am leaving for Iraq soon, and we are going to establish a lodge there.
Nowadays, with the internet, the first knock on the door of Masonry, is often an electronic knock. One lodge in Arlington VA, got 17 new petitions in one month, all from the internet. The Grand Lodge of New York has a state-wide lodge locator, and you can even download a petition form directly off the Grand Lodge website.
If you are interested in masonry, here is an excellent "capsule description"
Freemasonry Explained