In
NetHack, a ring is a
magical item that (usually) bestows its effects continuously -- they do not expend
charges, nor are they
invoked. You can only wear two rings at a time (one on each
hand). Each ring worn increases the rate at which you get
hungry by about 5%. A
ring of hunger will increase the rate by 50% (as will a
ring of regeneration). Some rings (like the
ring of adornment) are simply not worth wearing due to this effect.
Being blessed increases the effectiveness of certain rings. A cursed ring cannot be removed normally, in addition to possible other effects as noted -- this is extremely problematic with the ring of levitation and the ring of hunger, among others.
Rings can be eaten if you are polymorphed into a petrivore or metallivore. Eating a ring has a 1/3 chance of bestowing the ring's power as an intrinsic, if practical (ring of poison resistance); otherwise not (ring of levitation). In all cases the ring is lost. Some rings can be affected by the stone to flesh spell. This will transform it into a "meat ring", which is edible as food but loses all magical power.
NetHack rings include: