Regularly but I don't recally any specific instances. I know who and what I am, thus when I am told something about myself that is a flagrant lie, there is no cause for alarm or even reaction.
I do however have a funny story about homophobia.
First, it must be known that I currently live in a VERY conservative part of a VERY conservative state. This may be seen as important.
I decided some weeks back that I wanted to see a play. I had not seen one in more than a decade and thought that perhaps my tastes had changed enough over the years that it would be worth giving it another go. I already knew from past experience that my city has two Theater Companies. One is well regarded in the community and is known for competent acting and directing, the other is mostly known because of a play they presented where nudity was involved. Given that the respected theater company was not running a show, I decided on a whim to attend a play performed by the poorly regarded theater company. It was easy to justify of course - anything that causes moral outrage in my city is at least worthy of examination.
I did little reasearch beyond finding the venue and the time. The venue was a place called Outstanding Amarillo and after I arrived I found the play I was going to see was "Angels in America" - something of a controversial classic from Broadway that was made into a film at some point. I sat through the play and was unimpressed. The acting was spotty at best, with emotions that seemed out of place for scenes, forgotten lines and so forth and the play itself felt very rushed (it ran for about 90 minutes and I suspect it was designed as a 3 or 4 hour ordeal). As I started to leave, the man seated next to me who had been polite the entire time asked if I'd like to go "out" some time.
This seemed like an odd saying and after a bit of clarification I realized he was asking me out (I am male) on a date. I politely declined pointing out that my girlfriend would not approve of dating on the side. His reaction was almost comical - he was shocked I wasn't gay. My first reaction was to take offense until I realized the totality of circumstance.
The play's cast consists primarily of gay characters. The venue's name was a further clue as further investigation (i.e. looking at the sign) I found it was called OUTstanding Amarillo. That was their emphasis, not mine. Turns out this is a gay advocaty group. Just around the corner are the two gay bars in my city. My own attire, chosen at random, could have easily been seen as "flamboyant" were it not for the muted tones (I wear dark and earth colors because I have no capacity to understand if two objects match until it is pointed out). Thus, in a comically concservative city I had dressed flamboyantly and attended a play produced by a gay rights group that dealt primarily with the trials and tribulations of being gay in the 80s on the gay block of town. I suppose that considering all of that, the idea that I wasn't gay probably didn't even enter into the equation.