I can only tell you what worked for me: get the organization you want to interview with on the phone. Preferably the intern coordinator or her equivalent. Make up a reason, Oh, I just wanted to be sure I was directing my resume at the right person, blah blah blah whatever. That's a good all-purpose one. If you only get a receptionist, don't go into it, just leave a message, say you'll call back. Then call back if they don't call you back first. Once they're on the phone, then you can go into the whole "Oh I just wanted to be sure etc." Guess what? Now you've got the decisionmaker on the phone. You can sound enthusiastic and friendly, and attach at least a voice to a name. An email is easier to ignore than the person on the other end of the line. Best case scenario: you get into a convo and they offer you a spot right there. 2nd best case scenario: you set up an interview. 3rd best case scenario: you've established your interest with the decisionmaker and made an impression, thereby standing out from the hordes of emails, causing said decisionmaker to perk up when she finally sees your resume. Worst case scenario: you actually are sure that your app got to the right person.
Okay, actual worst case scenario: you acted like a feminine hygiene product on the phone and are now off the list. But that's entirely within your control.
Phone. You can't rely on them granting you interviews while you sit there passively, figuratively waiting for the phone to ring.
Anyway. Wait til after the fair if they are stressed right now, and then get a-calling.
(I didn't get any interviews for the fair I signed up for and it really wasn't a death knell. Try not to take it personally. Just move on.)