I sent a few hundred emails using a smart list filter this morning. 1.5 hours later, all are still showing in "pending" status. As a test, I chose one person and manually sent an email to this record. I got the same result. It is now several minutes and no email send.
Is there something wrong with Marketo today? I don't see any other messages, tweets, or indications of an outage. Emails sent fine yesterday using the same smart campaign.
If all emails are still pending after a few more minutes I would reach out to Support by logging a case or emailing firstname.lastname@example.org. They can diagnose the issue.
I did a batch send at 9:15 am PT today and didn't see any clicks until 10:21am PT -- What you said would seem to explain it, but looks like it did go, eventually.
This could have been caused by your instance being backlogged with other campaigns and not actioning the email send as immediately as desired. You can always verify that this is not the case by checking the "Campaign Queue" located at the top of Marketing Activities.
Additionally, I recommend subscribing to the alerts found here: Marketo Status
If Marketo isn't reporting issues and there are no campaigns in your backlog, then filing a ticket for support to review is always your best bet.