As South you open 1♠. What is your rebid over partner's responses of 1NT, 2♣, 2♦, 2♥, 2♠ and 3♠ (limit raise) respectively? EW are silent.

Solution

Over partner's 1NT response you bid 2♣.
Usually partner will now choose one of your black suits, thus giving preference, by either passing, or bidding 2(3)♠/3♣.
If he bids 2♦ or 2♥ however – he does not choose! – you pass. Partner conveys the message that he has a very long suit (at least a six card suit), which he could not bid at once over 1♠ – at the two level! – due to lack of points.

Over partner's 2♣ response you bid 3♣, if you are playing a standard system. You show minimal opening strength and four card club support.
However, more and more pairs have agreed upon playing 3♣ as a game forcing bid. For a good reason: how else can South show a good hand with a club fit (for instance 17-18 points and 5-4 in spades and clubs), worth a slam try, while not wanting to go beyond 3NT (because that is the contract to play if partner is minimal and does not have a spade fit). The disadvantage of this modern agreement is of course that you will have to rebid 2NT on your actual hand (not a major problem here, by the way).

Over partner's 2♦- or 2♥ response you bid 2NT. You show a minimal, balanced (or rather balanced...) hand. Do not bid 3♣, this game-forcing (!) bid shows extra strength (at least 15 points) since partner will 'automatically' bid 3NT if he has a guard in the other red suit, also if he has a minimal hand (10 points). Bidding a new suit on the three level, on a so far unlimited hand, when no fit has been established, is game forcing therefore. 

Over partner's 2♠ response you pass. Partner shows 6-9 points, including possible distributional points (since there is a known major fit), so game is not on.

Over partner's 3♠ response you bid 4♠. Partner shows 10-11 points and you have some extra strength in the two doubletons (each worth a distributional point).