What does 'go version' print?
go version devel +519230b4d06a Sun Apr 06 10:30:02 2014 -0400 + linux/amd64

What steps reproduce the problem?
The following program, which uses a WaitGroup to wait for two goroutines to complete,
should never exit.

package main

import (
        "fmt"
        "runtime"
        "sync"
        "sync/atomic"
)

func main() {
        for i := int64(0); ; i++ {
                wg := &sync.WaitGroup{}
                wg.Add(1)
                counter := int32(0)
                // spawn goroutine 1                                                                                                                        
                go func() {
                        atomic.AddInt32(&counter, 1)
                        wg.Done()
                }()
                runtime.Gosched()
                wg.Add(1)
                // spawn goroutine 2                                                                                                                        
                go func() {
                        atomic.AddInt32(&counter, 1)
                        wg.Done()
                }()
                // Wait for goroutine 1 and 2                                                                                                                   
                wg.Wait()
                if atomic.LoadInt32(&counter) != 2 {
                        fmt.Println(i, "Spurious wakeup from Wait()")
                        return
                }
        }
}

What happened?
It exits because of a bug in WaitGroup. (It may take a few minutes to fail.)

$ GOMAXPROCS=2 go run test.go
26994961 Spurious wakeup from Wait()