You better buckle down; it’s going to be awhile

Context is important in this one.  The speaker was attending a wedding and counting the hours until midnight.  This is a mash up of “buckle up” (get ready) and “hunker down” (to stay in a place).  The malaphor illustrates the common mix-up of directions (up, down) seen frequently in other postings on this site.  Thanks to Trey Compton for sending this one in!