From Thread Theory:
Classic pajama pants with mix and match details to suit any wearer. These straight leg pants are comfortable but not baggy. They feature an enclosed elastic waistband with the option of a drawstring to further perfect the fit. Pajama pants need not be boring to sew - these pants will teach you many of the essential techniques for sewing jeans and trousers in the future. Learn to install useful pockets and employ topstitching to create very functional and hardwearing loungewear.
Depending on skill level and preference, choose between a button fly, a simple mock fly or no fly. Also choose between minimal or detailed topstitching. Add an optional patch pocket for a bit of extra functionality!
This pattern, as part of the Parkland Casual Collection, is a classic garment that lends itself to creating the perfect casual, hand-made wardrobe for an active lifestyle.