So I have this alert sound that intermittently plays on my computer and I have no idea what it signifies or what application is causing it to occur. Is there a way to determine where such an alert is coming from? It's not one of the system alerts. Sounds Microsoft-y to me.
Many third-party applications do Growl-compatible notifications. If the alert's caused by a third-party program that supports Growl, you could install & configure Growl to identify it.
Apart from that suggestion, what's in your menubar? Could you press Cmd-Opt-Esc and post the resulting screenshot?