The August Visa Bulletin lists the family-preference category of F2A as "current" for all countries. What this means is that the spouses and children of Lawful Permanent Residents (green card holders) can receive immigrant visas as soon as their applications are approved. This is truly a rare event. In recent years, there has more typically been a backlog of two or three years for these visas. There is no telling just how long this lucky situation will last. If many application are received, the category may "retrogress" again. For this brief moment, however, a green card holder who marries his hometown sweetheart or has a child overseas need only wait a few short months to be reunited in the United States, rather than years.
The funny thing is, this is how many people who do not need to deal with our immigration system imagine that it always works. There is a sort of myth that once a person gets a green card, he can just bring the whole clan with him. The reality is that options for bring family to the U.S. are very restricted. There are many different routes to a green card. Most of these routes, but not all, will allow a person to include her spouse or children on the same application. However, a spouse or child "acquired" after a person gets a green card do not get this special treatment. Instead, the green card holder must file a separate petition for these new relatives. Normally, the family must then wait for years or find creative solutions to spend time together. The long wait times for visas are one of the driving forces behind illegal immigration, as families weary of separation are willing to risk being caught for the chance of living together.