I came out to my parents two months ago and I thought everything went okay, at least they didn't seem too upset, but now it's as if it never happened, they never mention that I'm gay. What's happening?
Parents, when they learn their child is gay, lesbian or bisexual, go through a series of stages, somewhat akin to the five stages of grief. Their first reaction is generally shock, then denial, guilt, questioning, and acceptance. It's not a quick or easy process: it generally takes parents anywhere from a couple of months to a couple of years to work their way through and many get stuck along the way.
It sounds as if your parents are stuck in denial. They were faced with the rather formidable task of trying to reconcile all the homophobic stereotypes and lies we've all (gay and straight alike) been brought up to believe with the reality of you, their gay child. It's not easy for a gay person to do, which is way the coming out process is measured in years for most people, and it's even harder for parents, who are older and more set in their thinking.
So the question really is, how can you nudge your parents along the path of acceptance? You could force a confrontation, demand that they recognize you for whom you really are, but you risk losing them all together.
Instead try nudging them a bit; when you tell them about your life don't de-gay yourself. That may not be as easy as it sounds since you are probably used to censoring yourself when you talk to them. Tell them about going to a meeting of the local gay club, or that you've joined your city's lesbian and gay band, or hiking club or going to a local PFLAG (Parents, Families and Friends of Lesbians and Gays) chapter meeting. Talk to them about your gay friends and mention that they are gay. If you have a boyfriend, let your parents know that you would like to introduce him and include him in the family.
In other words, let your parents know that being gay is more than what you do in bed, it's part of your life. They should get the message that if they want to keep you in their lives (and the vast majority of parents do) they will have to take you as you are, not as they would like you to be.
Other things you can do: