Sudoku
Classic 9×9 with hand-picked difficulty curves and a no-mark-ups expert mode.
Brain Boosters
A new corner of PBDesk for short, focused puzzles that sharpen the mind between Bits and Bites. Twenty minutes of arithmetic logic, one solved grid at a time — the kind of quiet focus that resets a working day. KenKen is here today; more games are queued.
1 game live4 difficulty tiers~200 hand-checked puzzles1 new puzzle every day
The first game is KenKen
All gamesNow playing
Arithmetic · Logic
KenKen
Fill an N×N grid so digits don't repeat in any row or column — the catch: outlined cages must hit their target with +, −, ×, or ÷. Pure logic, no guessing required.
3×3 → 9×9Grid sizes
10–25 minTypical solve
+ − × ÷Operations
Today's daily — Intermediate
A fresh hand-checked KenKen, the same all day. Refresh keeps your progress; come back tomorrow for a new one.
Coming next
Vote on what's next →Cryptic Mini
Five-clue cryptic crossword, finishable on a coffee break. Each solved clue links to its wordplay.
Logic Grid
Five-by-five attribute deduction puzzles — the kind your physics teacher used to print and hand out.
Why Brain Boost?
Single-task focus
Puzzles are one-pointed by design. Twenty minutes of nothing-but-this is a small luxury during a working week.
Working-memory workout
Mental arithmetic + spatial reasoning, in low-stakes reps. The "I can almost see it" feeling is the point.
Designed to be short
Every puzzle has a finish line within 30 minutes. No sprawling boards, no endless modes.
Daily ritual, no streak shame
A new puzzle every day, but we won't shake a finger at you if you miss one. Show up when you can.