Adding a new item to your iCal calendar can sometimes take a minute when you need to set its length, the alarms and a number of other settings. Remind Me Later is a free app that sits in your menubar and, when called upon, lets you enter a simple sentence that will be interpreted into an event on your calendar.
To use Remind Me Later, you initiate its text input either by clicking its menubar icon or pressing its hot key combination. From there, you can type in a natural sentence (such as "buy groceries at 4pm tomorrow") and it will translate that sentence into an iCal event.
In Remind Me Later's preferences you can choose whether or not to add an alarm by default and when that alarm should sound relative to the event. You can also choose the calendar to which events are added. Remind Me Later is really handy as it is, but in the future it would be awesome if calendars could be specified somehow (e.g. "Weekly Brainstorm at 1:30 PM Thursday @Lifehacker" to add to the Lifehacker calendar).
If you're an iCal user of any kind, Remind Me Later is an app you should download. It's available in the Mac App Store and for direct download, for free, right now.