Microsoft Office Outlook. De-facto standard for groupmail (email and calendar, for those of you who are lucky enough to have never heard that term) software in business. We are looking here at the Office 2003 version.
Go to the calendar view, and the sidebar on the right (unless you've turned it off), will show a mini version of that month, and probably your task list. Which, being me, is empty because my mind just doesn't function with task lists.
One reasonably useful feature is the ability to expand the monthly calendar list to show lots of months. So you do that, because you want to select something in the future. Then click on the title of the month you want.
WTF? No, you don't get that month displayed in front of you. In order to do that, you have to select a day, or range of days.
I must be tired: I can't really get up the energy to bitch about how uselessly and infuriatingly this breaks any reasonable conception of user interface user-friendliness.
So I'll leave with: Outlook, you suck.