So I called him, but he didn't answer. So I left a message asking him to call be back later, if he can.
Although, now that I think about it now...I'm still unsure as to whether or not I want to ask him about it. Mostly because my car is not with me right now (which he knows) so if I went, he'd have to pick me up (which is what he's been doing the last two weekends). It's one thing to kind of "invite yourself" but it's another to do that and ask for the person to pick you up. So yeah... I don't know if I can do that.
Now that I think about it, something similar to this happened last weekend too. He told me that him and some friends were going to a musical performance thing on Friday and asked if I wanted to go. I said that I'd think about it and let him know the next day. The next day, I called him and said I would go and he seemed very (happily) surprised that I even remembered. And I thought to myself, "Why wouldn't I remember? You just recently asked me if I wanted to go...and my memory is fantastic (see: ISTJ)" Now I'm think that if I wouldn't have called him up, he probably wouldn't have called me to ask if I was still interested since he assumed that I would forget about him or something.
WARNING: Frustrated ranting ahead. Proceed with caution or ignore.
EDIT: Ugh, I feel very frustrated right now. Not just about this situation since it's not that big of a deal (I recognize this), but about everything thus far. I just feel like I'm putting in all this effort and initiate things the majority of the time (once I do something, he'll be very attentive and start initiating things himself...but still, I have to start always) and I'm not getting any results. I still have no idea if he's interested in me (one day I think I know then the next I don't) and, at this point, I'm tired of trying to find out. So if he calls me back, I'm not even going to mention the movie. If he actually remembers that he invited me and wants to actually inform me of when they're going, then fine. If not, that's fine too. Then the next time I see him/we go out, I'm just going to flat-out ask him if he's interested in me and that will be that. I'm just so tired of all of this - I'm sorry, I guess I'm not used to these "feelings" and the stress that results from the uncertainty of everything.
If he likes me then I don't think it's too much to ask for him to "chase" me a little bit. Maybe he's secretly sitting in his room analyzing and over-analyzing and feeling frustrated as well, but I can't see that. In front of me he appears perfectly fine, like he probably wouldn't even notice if I didn't contact him for a week...but when I finally did he would probably be really happy about it. I don't understand. Everyone's been saying that he's been giving 'good signs' but what good are 'signs' with no result? This whole "trying to figure out someone else's feelings" thing is emotionally draining. Now I remember why I didn't do this in the past. =(
Actually I don't know if I'll even wait until we hang out again. Perhaps I should do it over the phone? Would that be the best way?