If a rim is cracked it may be possible to have it professionally welded. Otherwise, replace the rim. We do not suggest riding a bike with the rim cracked.     It is possible to ride a bike with a broken spoke in an emergency situation. Such as to get home. However, spokes are a structural part of the bike wheel and riding for excessive periods with a broken spoke will bend the rim causing the wheel to be permanently buckled. Spokes are replaceable. It is recommended to have a wheel trued by a professional wheel builder.