Go out and look for kitty, don't wait for them to come home. And the best time to go out looking is around midnight to 1 am, but don't wait to go out, especially if you saw them escape. At midnight, it's quiet and your cat would feel safer wandering around. Put out his/her used litter box. Your kitty won't have gone too far and is most likely within 3 or 4 houses from where they went missing. Take a flashlight with you, looking for eye reflections when looking under decks, cars, bushes etc. Quietly and calmly call kitty's name. Take treats and smelly nummy food with you and call them for treats in the same manner you would if you were at home. If you spot your cat, remain calm and if possible, sit down and let kitty come to you and the treats. Do not freak out or get overly emotional when you see, or finally capture your kitty, it could cause them to freak out and run away.
Check the City of Calgary impounded animals website. Also check the Calgary Humane Society lost and found website and any other shelter you can think of. Put up posters in your area and go door-to-door to see if your neighbours have seen your kitty.
Also, if microchipped, please ensure your information is currrnt on the chip registration. Never give up.