I use a calendar widget called WordPress Events Calendar. Every time I click inside the calendar widget, which should expand an event to show its description, a new window pops up that takes me to another page within my own blog.
The reason I don't suspect this to be a problem with the calendar widget is because this happened before when I made changes to the text widgets in my sidebar. The window that is popping up is a link I added today to the sidebar. I have no idea what kind of code could be messed up, but here is a link to my homepage:
This is the calendar:
If you click on any of the dates within the calendar, the Sponsorship page I just added today will open in a new window.