A simple idea – but good ideas usually are.
From the product website:
“Opening doors just got easier. Stop struggling with slippery door knobs! Great Grips go over round door knobs, creating a secure, slip-free grip. Grips glow for up to 8 hours so you’ll never fumble for a knob in the dark again! No tool installation — simply moisten with water and stretch to fit. Set of 2.“
Great Grips glow in the dark doorknobs are available for $11.95.